<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>flex三列布局</title>
  <link rel="stylesheet" href="../src/css-ui.css">
  <style lang="text/css">
    .wrap{
      display: flex;
      flex-direction: column;
      width: 100%;
      height: 100%;
    }
    .nav{
      flex:0 0 auto;
      width: 100%;
      height: 60px;
      border-bottom: 1px solid red;
    }
    .content{
      flex: 1 1 auto;
      width: 100%;
      overflow-y: auto;
      overflow-x:hidden; 
    }
    .foot{
      flex:0 0 auto;
      width: 100%;
      height: 60px;
      border-top: 1px solid red;
    }
    /* 页面蒙版 */
    .mask{
        position: fixed;
        top: 60px;
        bottom: 0px;
        left: 0;
        right: 0;
        background: rgba(0,0,0,.5);
    }
  </style>
</head>
<body>
  <div class="wrap">
    <div class="nav">111</div>
    <div class="content">
      <div class="tt-navbar">
        <a class="navbar-item">
          <span class="img"></span><span class="name">首页</span>
        </a>
        <a class="navbar-item active">
          <span class="img"></span>
          <span class="name">分类</span>
        </a>
        <a class="navbar-item">
          <span class="img"></span>
          <span class="name">发现</span>
        </a>
        <a class="navbar-item">
          <span class="img"></span>
          <span class="name">我的</span>
        </a>
      </div>
    </div>
    <!-- 页面蒙版 -->
    <!-- <div class="mask"></div> -->
  </div>
</body>
</html>